In a quadrupole mass spectrometer (QMS) including at least four rod-like electrodes to which a direct current voltage U and a high frequency voltage V cos(Ωt+Φ0) are applied, stability of an ion trajectory passing through a high frequency electric field generated among the electrodes is determined in a stable transmission area based on stability parameter values a and q illustrated in FIG. 3. The stability parameters a and q are expressed by the following Equations.
                    [                  Equation          ⁢                                          ⁢          1                ]                                                            a        =                              8            ⁢            eZU                                              Ω              2                        ⁢            m            ⁢                                                  ⁢                          r              0              2                                                          (        1        )                                [                  Equation          ⁢                                          ⁢          2                ]                                                            q        =                              4            ⁢            eZV                                              Ω              2                        ⁢            m            ⁢                                                  ⁢                          r              0              2                                                          (        2        )            
Here, a mass-to-charge ratio of a target ion is m/Z, r0 denotes a half value of a distance between rod-like electrodes facing each other, e denotes an elementary charge, U denotes a direct current voltage, and V and Ω denote an amplitude and an angular vibration frequency of a high frequency voltage.
Conventionally, in a tandem type mass spectrometry device including three stages of the QMS, in a first stage of the QMS (Q1), only an ion species having a specific mass-to-charge ratio m/z passes through Q1, and thus a voltage applied to an electrode is adjusted such that an operating point corresponds to a point near an apex of the stable transmission area as illustrated in FIG. 4a. In a second stage of the QMS (Q2), a specific ion species (parent ion) passing through Q1 is broken by collision induced dissociation, or the like to generate a dissociated ion (daughter ion). In this instance, in order to stably pass a daughter ion in a wide mass number range, the direct current voltage is set to U=0 and the same voltage V cos(Ωt+Φ0) as that in Q1 is applied as the high frequency voltage among the voltages applied to the electrodes in Q2 such that the operating point is on an a=0 axis, and the q value is the same between Q1 and Q2 as illustrated in FIG. 4a. 
In addition, as described in JP 2012-516013 A, in the second stage of the QMS (Q2), the direct current voltage is set to U=0, the amplitude of the high frequency voltage V cos(Ωt+Φ0) is the same as that in the case of Q1, and a frequency Ω/(2π) is set to be larger than or smaller than a frequency in Q1.